The following table shows the number of students scoring less than certain marks in an examination. Marks Less than 20 Less than 40 Less than 60 Less than 80 Less than 100 Number of students 10 20 45 50 60 The median marks of the students is :

Step-by-step solution

First, we convert the 'less than' cumulative frequency distribution into a standard frequency distribution. Class Interval Frequency ( f ) Cumulative Frequency ( C ) 0-20 10 10 20-40 20 - 10 = 10 20 40-60 45 - 20 = 25 45 60-80 50 - 45 = 5 50 80-100 60 - 50 = 10 60 Total number of students, N = 60 N 2 = 30 The cumulative frequency just greater than 30 is 45 , which corresponds to the class 40-60 . So, the median class is 40-60 . Here: Lower limit, l = 40 Cumulative frequency of the preceding class, C = 20 Frequency